1. Field of the Invention
The invention relates to an electrode comprising a minimum of two elements, and especially a neutral electrode in which two sub-electrodes are arranged in juxtaposition in a given direction and have facing edges running at an angle to the given direction.
2. Description of the Prior Art
A neutral electrode of the type described above operating with two flat sub-electrodes is known in the art, for example through German registered utility model 82 05 363 and German patent application No. P 36 23 293.9 (corresponding to U.S. patent application Ser. No. 035,690 filed Apr. 7, 1987 in the name of Feucht et al.).
It has been shown that a multi-element design of a neutral electrode is desirable when it is to be determined, through the use of a monitoring circuit, whether the neutral electrode is making a large surface contact, and not just point contact, with a patient during a surgical procedure. Such a monitoring circuit is described in German patent application No. P 35 44 443.6 having the title "Procedure and Circuit Arrangement for Monitoring the Indifferent Electrode of a HF-Surgical Apparatus for Flat Surface Contact" (corresponding to U.S. patent application Ser. No. 929,561). A monitoring circuit is also known in the art through U.S. Pat. No. 3,683,923.
In the forenoted German patent application No. P 36 23 293.9 it is stated that a simple fabrication of an electrode having a minimum of two elements is possible when the two sub-electrodes exhibit juxtapositioned facing edges that are at an angle to the given direction. In such a construction it is possible to attach connecting leads of equal length to the sub-electrodes. In this way fabrication is simplified. The routing of the conducting leads is also simplified.
It has now been shown that in the design of a multi-element neutral electrode, it is desirable to have a dependable and rapid indication of even a minimal lifting or peeling of a sub-electrode from the under layer or contacting surface at the patient, in order to eliminate harm to the patient. This is not the case, to the desired degree, in the application of essentially rectangular or trapezoidal shaped sub-electrodes and can be improved upon.
The basic object of the invention is therefore the continued improvement of an electrode of the kind referred to above in such a manner that a lifting or peeling may be rapidly and dependably detected through the use of a monitoring circuit.